Various surgical procedures are routinely carried out intravascularly or intraluminally. For example, in the treatment of vascular disease, such as arteriosclerosis, it is a common practice to invade the artery and insert an instrument (e.g., a balloon or other type of catheter) to carry out a procedure within the artery. Such procedures usually involve the percutaneous puncture of the artery so that an insertion sheath can be placed in the artery and thereafter instruments (e.g., a catheter) can pass through the sheath and to an operative position within the artery. Intravascular and intraluminal procedures unavoidably present the problem of stopping the bleeding at the percutaneous puncture after the procedure has been completed and after the instruments (and any insertion sheaths used therewith) have been removed. Bleeding from puncture sites, particularly in the case of femoral arterial punctures, may be stopped by utilizing vascular closure devices, such as those described in U.S. Pat. Nos. 6,090,130 and 6,045,569, which are hereby incorporated in their entireties by this reference.
Typical closure devices such as the ones described in the above-mentioned patents place a sealing plug at the tissue puncture site. Successful deployment of the sealing plug involves ejecting the sealing plug from within the closure device sheath to a location in alignment with and adjacent to the tissue puncture along an outer surface of the vessel. Misalignment of the sealing plug relative to the tissue puncture may result in improper sealing of the tissue puncture. Failure to contact the sealing plug against the outer surface of the vessel may also result in an improper seal.